Ambulatory Blood Pressure Monitoring - New Hypertension Diagnosis Guideline

In May 2011, the UK National Clinical Guideline Centre (NCGC) issued a guideline for managing adult primary hypertension. There is one key finding on diagnosis which is not familiar by most US doctors and consumers. The guideline recommends the routine use of ambulatory blood pressure monitor (ABPM) for making the initial diagnosis of hypertension. The measurements taken at the doctor's office should only be used as a screening tool. An ambulatory blood pressure monitor is one that the patient can carry 24-hours a day and can measure the blood pressure periodically.

The guideline further elaborates that measurements should be performed twice hourly and for a minimum of 14 measurements. A patient is considered to have hypertension if the daytime ambulatory blood pressure is above 135/85 mmHg. In another word, a patient should wear an ambulatory blood pressure monitor for a minimum of 7 hours to obtain 14 readings.

Except in severe cases, clinical blood pressure alone should not be used to start anti-hypertensive medications. A doctor should wait for the ABPM result before putting a patient on medicine.

There are two primary reasons driving this recommendation. The first one is cost and unnecessary medication. According to various studies, as much as 25% of patients can avoid taking medications if the ABPM readings were available. The second one is that night-time blood pressure is important to predict the risk of future health problems. If the patient is in the high risk category, the doctor can then take more aggressive actions.

Personally, the first reason is sufficient. I do not want to take any medications unless they are needed. They have side effects and they are normally expensive. Our health insurance cost is already too high and I have no urge to enrich the drug companies.

This recommendation is not well received in US and the following reasons are mentioned:

  • There is no evidence that ABPM will help managing the disease.
  • Ambulatory blood pressure monitor is expensive and not readily available.
  • US doctors and medical professionals are not trained in understanding the ABPM results.
  • The cost-benefit analysis may not apply to US, which has a multi-payer system.
  • Most insurance do not pay for blood pressure monitoring outside of medical facilities.

Things have been changing fast. Inexpensive ABPM has become available and a patient should be able to rent one for a day. Short classes are available for training medical professionals on using ABPM. In fact, software for analyzing the data is available today.

You can make up your own mind on whether these reasons are valid or not.

References

Nighttime blood pressure monitoring

Will ambulatory blood pressure monitoring before treatment become standard?

UK Guidelines Call for Routine 24-Hour Ambulatory Blood Pressure Monitoring in All Patients to Make the Diagnosis of Hypertension-Not Ready for Prime Time in the United States.